**4. Variability of crossbreeding of Crimean native grape varieties**

Previous studies have determined advisable parameters for assessment of the effectiveness of hybridization of grapes [17–19]. Broadly speaking, the analysis of the effectiveness of hybridization includes an assessment of the crossing ability of the initial forms, risk of loss of a valuable genotype and combination ability, heterosis and transgression [20]. For practical work following evaluation parameters are used:


Setting ability of seeds is estimated as a ratio of the number of seeds to the number of inflorescences taken into consideration [20, 21]. The pollination efficiency expresses the yielding of seeds relative to the theoretically possible number of seeds from all pollinated inflorescences of a particular cross-combination. Biological efficiency of hybridization reflects the efficiency of pollination, vitality and germinating ability of seeds, survival rate of seedlings in a hybrid nursery-garden, the yield of seedlings. Breeding efficiency of hybridization reflects the efficiency of pollination, the vitality and germination of seeds, survival rate of seedlings in a hybrid nursery-garden, the total yield of seedlings and the yield of economically valuable hybrids and may be used as a final assessment of the efficiency of hybridization, but it is somewhat subjective. 142 combinations of crossing of intraspecific and interspecific hybridization performed in the period 2005–2019 were analyzed


#### **Table 6.**

*The results of hybridization 2005–2018.*

(**Table 6**). The study included: as female forms - 10 native varieties of Crimea with a functional female type of flower; as male forms - the pollen of 25 complex interspecific hybrids, 7 varieties of the West European ecological-geographical group and 9 native varieties of the Don were used.

The selection of female forms was carried out on the basis of a complex analysis of prospects of the variety (productivity, crop quality). Since the formation of berries (and setting of seeds) carries the nature of biological features of original female variety and depends on the male form to a small extent [18, 22], it is important to study these parameters in native varieties and distinguish those with the maximum potential for reproduction.

The number of 19647 seeds and 6931 yearlings were obtained as a result of hybridization during pollination of 367 inflorescences. The biggest number of crossings was carried out with the participation of the female parents 'Sary Pandas' and 'Kok Pandas'. At the same time, the maximum number of seeds and hybrid seedlings per one cross-combination was obtained with the participation of the varieties 'Tashly' and 'Kefesiya'. Minimum number of seeds and hybrid seedlings per one combination of crossing was noted in the varieties 'Khersonesskiy' and 'Aibatly'. In combinations involving varieties 'Sary Pandas' and 'Kok Pandas', with the maximum number of inflorescences involved in hybridization, the percentage

**Figure 1.** *Crossing efficiency of native varieties of Crimea.*

#### *Biological Characteristics of Native Grape Cultivars of Crimean Region and Availability… DOI: http://dx.doi.org/10.5772/intechopen.98975*

of successful crossings was 93.4 and 75.6% respectively (**Figure 1**). Estimating the percentage of successful crosses, there is a tendency to its decrease with an increase in the number of cross-combinations (Pearson's pair correlation coefficient 0.9604).

Analysis of the results in the context of years showed that the most successful according to the parameters of crossbreeding were 2012 and 2016, and the least favorable were 2015 and 2018 (**Table 7**). Evaluating the variability of the parameter of setting ability of seeds in different years, it was noted that different varieties have high values, as presented in **Figure 2**.

From data presented in **Table 8** it follows that on average over the years of study maximum number of berries and seeds was obtained in cross-combinations involving 'Kok Pandas' variety. In different cross-combinations the female form of 'Kok Pandas' provides the biggest number of berries in one bunch – 62.0 pcs., by the number of fully formed seeds it has average value range - 1.25 pcs., but it still has the smallest fully formed seeds percentage of the total number- 66.7.

Varieties 'Khersonesskii' and 'Aibatly' form the smallest number of berries per one bunch of all studied grapevine cultivars – 5.8 and 8.3 pcs respectively. The number of fully formed seeds per one berry in combination with 'Aibatly' variety is quite high – 1.31 pcs. Combinations involving the varieties 'Kefesiya' and 'Tashly' provide a fairly high number of berries in one bunch – 59.1 and 48.1 pcs, the highest number of fully formed seeds per bunch is 1.59 and 1.77 pcs and the percentage of fully formed seeds is more than 90 of the total.


*\*- number of experiments is equal to the number of female varieties involved in hybridization.*

#### **Table 7.**

*Setting ability of seeds in different years of study.*

#### **Figure 2.**

*Changes in setting ability of seeds of 'Sary Pandas', 'Kok Pandas' and '*К*efesiya' grape varieties*


#### **Table 8.**

*Viability of hybrid seeds.*

Germination of seeds depends on hereditary strength, consisting in the fact that the necessary tissues and organs are formed and matured to ensure germination in appropriate conditions. Obtaining of seeds of low viability is determined by the female genotype long before the pollination [18, 22, 23].

Considering the parameters of seed germination with the participation of various native varieties, high data variability is noted (**Table 9**).

So in the cross-combinations with the participation of 'Aibatly' and 'Khersonesskii' varieties, the average number of seedlings per one cross-combination has a very low level - 7.2-16.2 pcs. Moreover, the seedlings obtained from fully formed seeds amount a very high percentage - more than 60.

In the total selection of the studied varieties, the female form 'Tashly' stands out, as it provides in hybridization the maximum number of seedlings per 1 combination of crossing, more than 100 pcs. The average percentage of seedlings obtained from full seeds is very low – 30.7 and the maximum level is 48%. The maximum variability of parameters of seed viability was noted in varieties 'Kok Pandas' and 'Sary Pandas'. Further, during the analysis of data for practical determination of the effectiveness of hybridization, we dwelt on the definition of 3 complex parameters: seeds setting; pollination efficiency; biological effectiveness of hybridization. **Table 10** presents these parameters in numerical terms, specific for the group of varieties under study and showing the range of variation of these parameters.

Analyzing the clustering results of the studied group of autochthonous varieties (**Figure 3**), we see that the varieties divided into 2 separate clusters: I – group, *Biological Characteristics of Native Grape Cultivars of Crimean Region and Availability… DOI: http://dx.doi.org/10.5772/intechopen.98975*


#### **Table 9.**

*Variability of parameter "germination of seeds".*


#### **Table 10.**

*Effectiveness of hybridization of native varieties.*

**Figure 3.** *Multifactorial hierarchic classification of genotypes under study by the effectiveness of their hybridization.*

consisting of 3 varieties: 'Kok Pandas', 'Kefesiya' and separate variety 'Tashly'; II – group, including 7 varieties – divided into 2 big subclusters: а) varieties 'Aibatly' и 'Khersonesskii'; b) 'Krona', 'Kokur Chernyi' and separate varieties 'Sary Pandas', 'Misgiuli Kara' and 'Misket'.

A group of varieties including 'Kefesiya', 'Kok Pandas' and 'Tashly', was selected in the analysis and demonstrates high hybridization efficiency in intraspecific crossing and in crossing with complex interspecific hybrids. Varieties 'Sary Pandas' and 'Misgiuli Kara' are distinguished by low setting ability of seeds, however, the biological effectiveness of hybridization remains at the level of group 1. Thus, we can confirm that female parent varieties 'Sary Pandas' and 'Misgiuli Kara' are specific in issues of crossing ability and viability of hybrid seeds.
